Fluid motor and lubricating means therefor



Oct. 10, 1950 R. sTEvENsoN ETAL FLUID MoToR AND LUBRICATING MEANSTHEREFOR Original Filed Oct. 5, 1942 Ykv,

Patented Oct. 10, 1950 FLUID MOTORANI) LUBRICATING MEANS THEREFOR RobertStevenson, Barrington, and Alexander W.

Keema, Providence, R. I., assignors to Merit Engineering, Inc.,

Island a corporation of Rhode Original application October 5, 1942,Serial No. 460,794, now Patent No. 2,344,473, granted March 14, 1944.

Divided and this application January 14, 1944, Serial No. 518,289

V1 This invention relates to a remote control apparatus of the type inwhich the transmission of movement from one actuating -unit to anotheractuated unit is by liquid or hydraulic means and is a division of ourco-pending application Serial No. 460,794 iiled October 5, 1942, whichhas now Vissued in Patent No. 2,344,473.

Although the transmission in a remote control apparatus has beenheretofore done by hydraulic means in which a piston moves the liquid oris moved by the liquid at theremote location it is quite usual toactuate the piston and have the piston in turn actuate some mechanicallink and lever arrangement for the transmission or conversion of powerto or Afrom the actuating' piston. Such linkages and leverages becomemore or less easily worn and they are materially retarded by friction. iY

One of the objects of this invention is to provide an improved means foractuating the piston in the actuating unit and an improved meansactuated by the piston in the actuated unit.

Another object of this invention is to provide a control which will berelatively free from friction.

Another object of this invention is tovprovide a mechanical operatingpart acting' in a liquid which will act as a lubricant for the movementof these parts one upon the other.

Another object of this invention is to provide the transmission ofrotary movement to longitudinal movement through a screw action and viceversa whereby a positive conversion of Inovement from one direction tothe other may be provided.

Another object of this invention is to provide an automatic means formaintaining liquid in a hydraulic transmission from one lunit to theother always full to capacity.

Another object ofthis invention is to provide a means to control thereacting hydraulic pressure which acts upon the threaded member throughwhich movement` Ais applied to the actuating piston.

Another objectof the invention is to provide a construction having atheoretically unlimited angular rotation.

With these and other objects in view, the invention consists of certainnovel features of con- -struction, as will be more fully described andV2 claims. (ci. (so-54.6)

Fig. 2 yis a similar section showing upon a larger scale a differentposition of the actuating unit;

Fig. 3 is an elevation of the actuating screw or threaded shaft;

Fig. 4 is a section on line --fl of Fig. 2;

Fig. 5 is a section on line 5--5 of Fig. 2;

Fig. 6 is a perspective view of the collar in which the valve ismounted;

Fig. 'l is a sectional view showing this collar and valve assembly withthe removable valve seat which is mounted in the piston. i

In proceeding with this invention we have provided two units having aconduit connecting them. Each unit contains a chamber communieating withthe conduit connecting the units and pistons provided in the chambers,so that when one piston is moved to diminish the volume of liquid in thechamber the liquid is forced into the chamber in the other unit andforces the piston therein in a direction so that this unit increases itsamount of fluid as the piston moves to provide for it. The piston in theactuating unit is moved by a shaft having screw threads thereon while athreaded shaft in engagement with the piston in the actuated unit isrotated in response to axial movement of the piston in this actuatedunit.

With reference to the drawing IB designates the actuating unit and l lthe actuated unit while i2 designates a conduit which may be of anydesired length or shape which will transmit liquid from one unit to theother and which acts as the sole means of connecting the units together.The actuating unit Il! comprises a body I4 of generally cylindricalshape which has a cylindrical bore l5 extending inwardly from one end inwhich a piston IB is slidably mounted. The bore of the body is reducedin diameter as at il so as to provide an abutment shoulder I8 betweenthe bores l5 and il whilerthe bore formed from the opposite end is ofone size at I9 substantially the same size as bore i5 and larger as at2l).

The rpiston I6 in the bore l5 has packing or piston rings 2l to preventthe passage of fluid along its surface which contacts with the bore l5.This piston is reduced as at 22 to slide in the bore I1 while thisextending tubular portion 22 is internally threaded as at '23 to engagethe thread of the shaft 24 which is rotatably mounted by means of a ballbearing 25 in the body i4, which ts snugly in the bore 2i) of this bodyportion. A bearing 26 is also located in the bore 2E! of the body andserves as a sliding mounting for the nut 2l which has threadedengagement with the threads of the shaft 24. This bearing 26 is lockedin place by a pin 28. A closure cap 29 for the end of the body issecured in place by mounting bolts 30 to close one end of the bore ofthe unit i0. This cap contains in a suitable recess therein a sealingunit 3| to prevent the escape of fluid which is contained in the unit.An operating handle 32 is secured in place by nut 32 on the end of theshaft 24. Spring 33 is under compression and acts between the nut 2'!and a washer 34 which abuts against the end of piston collar 2'2 andtends to force these two threaded parts against which it presses inopposite directions thus providing a balanced action on the shaft.

An end wall 35 is secured to the body by bolts 36 to close the bore I5.This end Wallis provided with an opening 3i to which the conduit l2 isdetachably connected. Liquid is located in the chamber 38 to be forcedby the piston I6 through the conduit I2.

A cylindrical shell Ml surrounds the body I4 and telescopes the portion@I at one end and the portion 42 at the other end of the body which arelarger thanthe intermediate portions of the body so as to provide anannular chamber 43 in the space about the body'lf-l. rEhe body isprovided with an axially extending conduit @il which communicateswith'chamber i3 and the radially extending conduit l5 located in thehanged portion 48 of the body and to some convenient reservoir of supplywhich will provide such a head as to cause liquid to now into andmaintain the chamber [i3 full' of liquid.l

The piston l has a centralinternally threaded bore 48 into which a unitdesignated generally .9 and shown in Fig. 7 is threaded.Y This unitcomprises a cylindrical portion 50 having a flange 5I and an end Wall 52which is provided with a valve seat 53 in which'there is located'a valve53 having a tapered sealing surface 55 to engage with the seat andenclose the same. On the end of this valve an' abutment and guide collar56 is secured by means of a pin extending through opening 51 in thecollar and through the end of the valve while a spring 58 abuts thecollar 56 and forces thevalve to its seat. The collar 56 sndabiy nts theportion 5u and'extends a substantial'distance rearwardly of the unit 49'so that when the piston is moved to completely retracted position thiscollar 5G will engage the end of the shaft 2li and force the valve fromits seat to the dotted linepositicn shown in Fig. 7, the valvebeingshown in closed position and as spaced from the shaft-24 in Fig..2; Grooves 58 are provided in the collar 5S to provide communicationwith the interior of unit 49 'so that liquid in the chamber i3 may passthrough the radial conduit 88 in the body andI 50' in the piston toprovide a communication between the supply reservoir 43 and itsreservoir or chamber 38 when the piston is in retracted position. Thus,should there be any leakage in the system the reservoir would supplythat liquid which'may have escaped at each retraction of the piston.

The actuated' unit designated generally Il is generally similar to theactuating unit I8. It comprises a body 65 having a cylindrical bore 66extending from one end which is reduced as at 8l and thenagain enlargedas at 88 and further enlarged at 89. The piston 18 slides in the bore 68with its packing or' piston' rings 'Il to prevent passage 'of liquidalong'between the bore and the piston;` On one side of the piston is achamber 'I2 which communicates' withV a conduit l2. The piston' istubular having a cavity .113 which is closed by a plug M instead of avalve as shown in connection with the other actuating unit. The reducedportion of this piston 15 is internally threaded as at 'i6 so as to havea threaded engagement with the shaft l1 which carries thread 78, whilethis portion is keyed as at 19 to slide along the bore 61 in the body65. Shaft 'l'l is rotatably mounted in the body by fmeans of the ballbearing unit 88 while leakage is prevented by a sealing means 8l whichis housed in the closure cap 82 for the end of the body 85 which is heldin place by the mounting bolts 83. A lever 84 is fixed to the shaft 'l1so that as this shaft rotates this lever will swing to do such work asis required of it. A spring 88 acts against an abutment washer 85 andalso against an abutment washer Sl which engages one end of the pistonso as to urge the piston axially in a direction to decrease the volumeof liquid in the chamber "52. The pitch of the plural threads is suchthat an axial thrust of the piston will cause rotation of the shaft. Anend wall 88 is secured by bolts 83 to close one end of the body 65 andisrprovided with an opening 89 for threadingly connecting conduit I2 tothei unit.

A shell 90 is positioned about the body 65 and provides an annularchamber 9| which may contain fluid of a lubricating nature and which mayconnect through conduit 92 with the space 93 in which the spring 85 islocated. By reason of this arrangement an expansion chamber is formedfor any liquid which may be utilized to lubricate the shaft uponretraction of the piston from the position shown in Fig. l. f

The spring 86 will at all times even when under compression exert lessforce upon piston 15 than will the spring 33 exert'upon piston I6.Accordingly the lever 84 will remain in position after it has beenactuated to a certain predetermined point; rThe pitch of Athe screws orthreads on shafts 'H and 24 will be the same so that a corre'- spondingmovement of these shafts =will be caused. Spring 33 although acting inone direction'on the piston tending to move the shaftll'is compensatedfor by the same action of'this spring upon nut'l in vthe oppositedirection, which nut also serves to maintain the springv at'constantstrength and therefore "at uniform pressure. Thus, any thrust which iscaused by this spring tending to move the shaft 24 in one direction isneutralized by a thrust in the opposite direction of nut 2l tending toturn'the shaft in the opposite direction and therefore by thisarrangement the shaft is in balanced relation and there is no tendencyto rotate the shaft in either 'direction from the spring 33. Further,any pressure of the liquid on piston I6 because of this spring 33 willnot rotate the shaft 24.

In operation, assuming the chamber 38 'and chamber 'l2 and the conduitconnectingthem are full of liquid and the lever 32 has been movedsufficiently so'that the valve 511 is closed, at which point the handle82 and the lever 83 are both'located in the same angular position ofrotation relative to the axis of the shafts 2li and Tl, then any furthermovement of the lever 32`which will force the piston I6 to decrease thesize of the chamber 38 will cause the iiuid to pass through the conduitl2 and correspondingly increase the size of the chamber l2 which is ofthe same diameter by causing the piston 'I8 to be axially moved thereinwhich in turn Willcause 'a rlotation of the shaft 'ilV andcorrespondingly Vmove lever 8d to cause it toangularly move handle 132at some point remote from the location'goffzthe unit I8. The length ofthe chambers 38'ian`dst12 rrevolutions of the lever Sil.

may be such as to cause one or more complete If, however, it is desiredto retard or move the lever 84 in the opposite direction it is merelynecessary to move the hand lever 32 in such opposite direction whichwill Withdraw the piston I5 in the unit Il] and spring 35 Will be ofsuch strength as to force the piston 73 to move the fluid out of thechamber 72 back into the chamber 38 through conduit I2 and willcorrespondingly turn the shaft 11 to retard the lever 84. After completeretraction of the lever 8d through movement of the piston 12 to the endof its stroke a further movement of the piston I6 by means of the handle32 is permitted so that the valve 54 may be opened and any liquid whichmay have escaped from the system Will be replenished automatically byreason of a sufficient head on the supply liquid which Will force itinto the actuating part lof the system. A drain may be provided at plug95 if desired for the escape of any liquid into the chamber 9|.

We claim:

l. In a huid motor device for a remote control apparatus, a body havinga piston chamber sealed at each` end thereof, a piston movable thereinin 'one direction by the injection of fluid into said piston chamber onone side of the piston, said piston chamber having a lubricating fluidtherein on the opposite side of said piston, a spring acting on saidpiston to move it in the opposite direction, internal threads in saidpiston and a threaded shaft having its threads engaging the threads ofthe piston and extending from said piston chamber, a lever on saidshaft, the threaded connection between said piston and shaft being ofsuch a pitch that rotary movement of said shaft and lever occur uponaxial movement of said piston and a shell surrounding said body and inspaced relation thereto providing an annular chamber surrounding saidbody and extending substantially the full length thereof, said pistonchamber having on the said opposite side a conduit therein opening intosaid annular chamber, said annular chamber serving as an expansionchamber for receiving the lubricating fluid Number on the other side ofsaid piston when said piston is moved in the said one direction.

2. In a fluid motor device for a remote control apparatus, a body havinga piston chamber Sealed at each end thereof, a piston movable therein inone direction by the injection .of fluid into said piston chamber on oneside of the piston, said piston chamber having a lubricating fluidtherein on the opposite side of said piston, a spring acting on saidpiston to move it in the opposite direction, internal threads in saidpiston and a threaded shaft having its threads engaging the threads ofthe piston and extending from said piston chamber, a lever on saidshaft, the threaded connection between said piston and shaft being ofsuch a pitch that rotary movement of said shaft and lever occur uponaxial movement of said piston and a shell surrounding said body and inspaced relation thereto providing an annular chamber surrounding saidbody, said piston chamber having an opening on the said opposite sideextending into said annular chamber, said annular chamber serving as anexpansion chamber for receiving the lubricating fluid on the other sideof said piston when said piston is moved in the said one direction, andmeans for draining said expansion chamber.

- ROBERT STEVENSON.

ALEXANDER W. KEEMA.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Name Date Hayes Aug. 18, 1874 Fuller Oct. 27, 1931Taylor Oct. 3l, 1933 Nardone Mar. 13, 1934 Levy May 27, 1941 Warner June16, 1942 FOREIGN PATENTS Country Date Great Britain Aug. 3, 1937 Number

